The invention discloses a lansoprazole nano-particle frozen preparation for injection capable of simultaneously improving the stability and dissolubility, and a preparation method thereof. The preparation comprises the following components in parts by weight: 20-40 parts of lansoprazole, 5-50 parts of dextran, 5-40 parts of sodium sulfite, 5-60 parts of solubilizer, 10-100 parts of nano-carrier material and 10-100 parts of freeze drying excipient. The preparation method comprises the steps of: adding the dextran, the solubilizer and the sodium sulfite into a liquid preparation tank, adding water for injection and stirring until dissolved, regulating the pH value, adding the lansoprazole and the nano-carrier material, continuing to stir evenly, adding the freeze drying excipient and stirring until dissolved, supplementing the water for injection to the full dose, decoloring, finely filtering, subpackaging and freeze drying to obtain the frozen preparation.